But transport heads have rejected another proposed remedy for them to take official naps during their shifts.

Transportation Secretary Ray LaHood said the government would not pay controllers to sleep while on duty and that federal officials "take very seriously" their obligation to solve the problem of sleeping controllers.

He also says "controllers have to make sure that they get the right rest and they come to work rested".

Mr LaHood announced earlier that the FAA was adding an hour to the minimum amount of time controllers must be off between shifts.

He said that under the new plan, when controllers report for work, "hopefully they're rested". He also said officials will tour airport towers this week to discuss the problems of sleeping on the job with controllers.

Five cases of sleeping controllers have been disclosed since late March.

The latest one occurred just before 5am on Saturday at a busy regional radar facility that handles high altitude air traffic for much of Florida, portions of the Atlantic Ocean and the Caribbean Sea.

Several other countries, including Germany and Japan, permit controllers to take sleeping breaks and they provide quiet rooms with cots for that purpose.

It has been an open secret in the US Federal Aviation Administration dating back to at least the early 1990s that controllers sometimes sleep on the job. Controllers have said privately that many take a nap on purpose. On midnight shifts, one controller will work two positions while the other one sleeps and then they switch over.